On 19:38 Mon 06 Feb , Karol Lewandowski wrote:
> On 05.02.2012 11:38, Jean-Christophe PLAGNIOL-VILLARD wrote:
>
> Hi!
>
> >+Device-Tree bindings for i2c gpio driver
> >+
> >+Required properties:
> >+ - compatible = "gpio-i2c";
>
> Driver name is "i2c-gpio" in file i2c-gpio.c. Previous version of
> patch adding DT-support (prepared by Thomas Chou[1]) used i2c-gpio -
> could we stick to that name?
>
> [1] https://lkml.org/lkml/2011/2/23/584
>
> >+ - gpios: sda and scl gpio
> >+
> >+
> >+Optional properties:
> >+ - gpio-i2c,sda_is_open_drain: sda as open drain
> >+ - gpio-i2c,scl_is_open_drain: scl as open drain
> >+ - gpio-i2c,scl_is_output_only: scl as output only
>
> Most of DT-properties I've seen used hyphen, not underscore. Could
> we stick to that convention?
>
> (Nitpick: I think that "is" in property names is redundant too.)
>
> >+ - udelay: half clock cycle time in us (may depend on each platform)
>
> Could we use "clock-frequency" as Grant have suggested during review
> of previous patch to i2c-gpio?
as exaplained no as for gpio the delay is platform dependent
>
> https://lkml.org/lkml/2011/2/24/220
>
> >+ - timeout: timeout to get data
> >+
> >+
> >+Example nodes:
> >+
> >+i2c-gpio@0 {
> >+ compatible = "gpio-i2c";
> >+ gpios =<&pioA 23 0 /* sda */
> >+ &pioA 24 0 /* scl */
> >+ >;
> >+ gpio-i2c,sda_is_open_drain;
> >+ gpio-i2c,scl_is_open_drain;
> >+ udelay =<2>; /* ~100 kHz */
> >+ #address-cells =<1>;
> >+ #size-cells =<0>;
> >+
> >+ rv3029c2@56 {
> >+ compatible = "rv3029c2";
> >+ reg =<0x56>;
> >+ };
> >+};
> >diff --git a/drivers/i2c/busses/i2c-gpio.c b/drivers/i2c/busses/i2c-gpio.c
> >index a651779..6b5d794 100644
> >--- a/drivers/i2c/busses/i2c-gpio.c
> >+++ b/drivers/i2c/busses/i2c-gpio.c
> >@@ -14,6 +14,8 @@
> > #include<linux/module.h>
> > #include<linux/slab.h>
> > #include<linux/platform_device.h>
> >+#include<linux/of_gpio.h>
> >+#include<linux/of_i2c.h>
> >
> > #include<asm/gpio.h>
> >
> >@@ -78,16 +80,51 @@ static int i2c_gpio_getscl(void *data)
> > return gpio_get_value(pdata->scl_pin);
> > }
> >
> >+static int of_i2c_gpio_probe(struct device_node *np,
> >+ struct i2c_gpio_platform_data *pdata)
> >+{
> >+ u32 reg;
> >+
>
> if (of_gpio_count(np) < 2)
> return -EINVAL;
ok
>
> >+ pdata->sda_pin = of_get_gpio(np, 0);
> >+ pdata->scl_pin = of_get_gpio(np, 1);
>
> if (pdata->sda_pin < 0 || pdata->scl_pin < 0)
> return -EINVAL;
>
> >+
> >+ if (of_property_read_u32(np, "udelay",®))
> >+ pdata->udelay = reg;
> >+
> >+ if (of_property_read_u32(np, "timeout",®))
> >+ pdata->timeout = reg;
> >+
> >+ pdata->sda_is_open_drain =
> >+ !!of_get_property(np, "gpio-i2c,sda_is_open_drain", NULL);
> >+ pdata->scl_is_open_drain =
> >+ !!of_get_property(np, "gpio-i2c,scl_is_open_drain", NULL);
> >+ pdata->scl_is_output_only =
> >+ !!of_get_property(np, "gpio-i2c,scl_is_output_only", NULL);
> >+
> >+ return 0;
> >+}
> >+
> > static int __devinit i2c_gpio_probe(struct platform_device *pdev)
> > {
> > struct i2c_gpio_platform_data *pdata;
> > struct i2c_algo_bit_data *bit_data;
> > struct i2c_adapter *adap;
> > int ret;
> >+ int len = sizeof(struct i2c_gpio_platform_data);
> >
> >- pdata = pdev->dev.platform_data;
> >+ pdata = kzalloc(len, GFP_KERNEL);
>
> Could you also take into account Grant's comment about
> private/platform data?
>
> https://lkml.org/lkml/2011/2/3/221
>
> > if (!pdata)
> >- return -ENXIO;
> >+ return -ENOMEM;
> >+
> >+ if (pdev->dev.of_node) {
> >+ of_i2c_gpio_probe(pdev->dev.of_node, pdata);
>
> Above might fail if configuration is corrupted.
>
> >+ } else {
> >+ if (!pdev->dev.platform_data) {
> >+ ret = -ENXIO;
> >+ goto err_alloc_adap;
> >+ }
> >+ memcpy(pdata, pdev->dev.platform_data, len);
> >+ }
> >
> > ret = -ENOMEM;
> > adap = kzalloc(sizeof(struct i2c_adapter), GFP_KERNEL);
> >@@ -143,6 +180,7 @@ static int __devinit i2c_gpio_probe(struct
> >platform_device *pdev)
> > adap->algo_data = bit_data;
> > adap->class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
> > adap->dev.parent =&pdev->dev;
> >+ adap->dev.of_node = pdev->dev.of_node;
> >
> > /*
> > * If "dev->id" is negative we consider it as zero.
> >@@ -154,6 +192,8 @@ static int __devinit i2c_gpio_probe(struct
> >platform_device *pdev)
> > if (ret)
> > goto err_add_bus;
> >
> >+ of_i2c_register_devices(adap);
> >+
> > platform_set_drvdata(pdev, adap);
> >
> > dev_info(&pdev->dev, "using pins %u (SDA) and %u (SCL%s)\n",
> >@@ -172,6 +212,7 @@ err_request_sda:
> > err_alloc_bit_data:
> > kfree(adap);
> > err_alloc_adap:
> >+ kfree(pdata);
> > return ret;
> > }
> >
> >@@ -192,10 +233,20 @@ static int __devexit i2c_gpio_remove(struct
> >platform_device *pdev)
> > return 0;
> > }
> >
> >+#if defined(CONFIG_OF)
> >+static const struct of_device_id gpio_i2c_dt_ids[] = {
> >+ { .compatible = "gpio-i2c", },
>
> There seem to be no good reason to make DT-compatible string
> different from driver's name that's already in use:
>
> > static struct platform_driver i2c_gpio_driver = {
> > .driver = {
> > .name = "i2c-gpio",
>
> Regards,
> --
> Karol Lewandowski | Samsung Poland R&D Center | Linux/Platform
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